The invention belongs to the technical field of food, and particularly relates to a biscuit with the effects of purging the gut, detoxifying, maintaining beauty and keeping young and a preparing method thereof. The biscuit is prepared from wheat flour, quinoa flour, oat flour, chia seed powder, potato flour, white kidney bean flour, whey protein powder, trehalose, resistant dextrin, white granulated sugar powder, red-yeast millet flour, Chinese-soapberry-fruit peel powder, jasmine flower extract, coconut oil, sodium bicarbonate, ammonium bicarbonate and salt. The biscuit with the effects of purging the gut, detoxifying, maintaining beauty and keeping young does not contain a preservative and an artificially-synthesized sweetening agent, the compatibility of components of all raw materials is scientific, paste forming is easy, and the made biscuit is high in dietary fiber content, balanced in nutrition, fragrant and sweet, delicious, good in quality and low in fat and sugar; the obvious satiety feeling exists after the biscuit is eaten, and the biscuit has the obvious effects of losing weight, purging the gut, detoxifying, maintaining beauty, keeping young and the like.